In the aforementioned first and second vehicle types with either left-hand or right-hand drives, each variant is equipped with five sets of harnesses: front, floor, rear, cowl and instrument harnesses. The wiring system for each set of harnesses depends on the type of vehicle and the position of the steering wheel. This fact forces manufacturers to prepare varieties of harnesses in order to accommodate for these different versions, and thus causes manufacturing cost to be relatively high.
In Japanese patent application published before examination under the number 8-216 805, there was envisaged a wiring harness system connecting electrical source distributors to different kinds of apparatus. With this system, there was proposed a method of shortening with harness length, irrespective of the position of the steering wheel. However, this document is not related to the problem of rationalizing the whole harness system in vehicles of different types or variants.
FIG. 1 shows a typical front harness A for a right-hand drive, four-door vehicle having a ledged tail. The front harness A has a U-shaped path, the open side of which faces the driving direction, and a connector a on the corner at the right side. To this connector a is connected a cowl harness and an instrument harness B through a connector B1. The front harness is connected to a combined harness C integrating a floor harness and a rear harness, through connectors b2 and c, provided at the right side of the instrument harness B. The combined harness C passes through the right side of the vehicle body towards its rear part and forms therein an inclined U-shaped path, such that the path is open towards the left side of the vehicle body, as seen from the Figure.
In the above wiring harness, a stop switch 1 of a brake pedal is connected to the instrument harness B to the right of the steering wheel 2, on the right-hand side. Stop lamps 3 are connected to the transversal rear end part of the combined harness C, so as to be turned on or off by the switch 1.
FIG. 1(B) shows a same type of four-door ledged tail vehicle as described above, but the vehicle is in this case a left-hand drive version. A front harness E is connected to an instrument harness F through connectors e and f1. The instrument harness F is then connected to a combined harness G integrating a floor harness and a rear harness through connectors f2 and g. The combined harness G passes through the left side of the vehicle body towards its rear part and forms therein an inclined U-shape path, such that the path is open towards the right side of the vehicle body.
In the above left-hand drive vehicle, a stop switch for the brake pedal is connected to the instrument harness F to the left of the steering wheel and therethrough to the combined harness G. Stop lamps 3 connected to the combined harness G are thus lit on or off by the switch 1.
In the above ledged-tail vehicles, the combined harnesses C and G installed in the rear part are in the form of an inclined U having rightward or leftward opening. This structure makes it possible to shorten the connecting pathway to electrical fixtures such as the stop lamps.
FIG. 1(C) shows a four-door ledgeless-tail vehicle with right-hand drive. In this case, a front harness A and an instrument harness B have the same and common path as those in the case of the four-door ledged-tail vehicle with right-hand drive, shown in FIG. 1(A). A combined harness D integrating a floor harness and a rear harness is then connected to a connector b1 of an instrument harness B, through a connector d located at the right side of the vehicle. The combined harness D forms a reversed U-shaped path in the rear part of the vehicle, being open towards the backward direction thereof.
FIG. 1(D) shows a four-door ledgeless-tail vehicle with left-hand drive. In this case, a front harness E and an instrument harness F have the same and common path as those in the case of the four-door ledged-tail vehicle with left-hand drive shown in FIG. 1(B). A combined harness H integrating a floor harness and a rear harness is then connected to a connector f2 of the instrument harness F, through connector h located at the left side of the vehicle. The combined harness H forms a reversed U-shape path, the open side of which faces the backward direction of the vehicle.
In the above ledgeless-tail vehicles, the combined harnesses D and H have the rearwardly-turned opened U-shape, so that there is no obstacle when loading or unloading luggage or goods through the rear door.
FIGS. 2(A) to (D) show the connection position of a turn indicator light switch 5 for turn indicator lights 4, corresponding to each type of vehicle shown in FIGS. 1(A) to (D). In the four-door ledged-tail vehicle (A) and four-door ledgeless-tail vehicle (C), respectively with right-hand drive, the turn indicator light switch 5 is connected to an instrument harness B to the right of the right-hand-side steering wheel 2. By contrast, in the four-door ledged-tail vehicle (B) and four-door ledgeless-tail vehicle (D), respectively with left-hand drive, the turn indicator light switch 5 is connected to an instrument harness F to the right of left-hand-side steering wheel 2.
Further, as in shown in FIGS. 1 and 2, a battery 6 is located at the leftward position in the front part (engine compartment) of the vehicle.
In the right-hand drive vehicles of the ledged-tail A and ledgeless-tail (C) types in FIG. 1, harnesses A and B constitute the common paths, but harnesses C and D do not. On the other hand, in the left-hand drive vehicle of ledged-tail (B) and ledgeless-tail (D) in FIG. 1, there is no common path with the right-hand drive vehicle. In addition, although harnesses E and F are common for the ledged-tail and ledgeless-tail types, harnesses G and H are not. Consequently, the above-mentioned four types of vehicles need eight different sets of harnesses A to H.
Table 1 shows the number of different harness sets to be prepared per number of vehicles according to the known art. When the ledged-tail vehicles with right-hand or left-hand drive, and the ledgeless tail vehicles with right-hand or left-hand drive, are manufactured in quantities of 1,000, 1,000, 500 and 500 respectively per month, the requirements are: 1,500 units each of harnesses A, B, E and F, 1,000 units each of harnesses C and G, and 500 units each of harnesses D and H.
As described above, the four types of vehicles (including the left-hand and right-hand drive variants) already calls for eight sets of harnesses. The increase in set number makes it difficult to efficiently manufacture harnesses and raises manufacturing costs.